Arrangement for effecting uniform load distrubution on climbing jacks

ABSTRACT

An arrangement for a uniform load distribution and a group of cooperating climbing jacks in which each jack in the group acts on a separate climb rod and includes one or more lifting means. Each climbing jack has associated therewith at least one load transferring hydraulic balancing jack embodying a hydraulic pressure cylinder and hose means hydraulically interconnecting the pressure cylinders of the balancing jacks associated with the group.

United States Patent [72] lnventor Rolf GustafJohansson Saltsjo-Duvnas, Sweden [2]] App]. No. 708,362

[22 Filed Feb. 26, 1968 [45] Patented Jan. 19, 1971 [73] Assignee A B Byggforbattring Stockholm, Sweden a Swedish joint stock Company [32] Priority Mar. 3, 1967 [33] Sweden [54] ARRANGEMENT FOR EFFECTING UNIFORM LOAD DISTRUBUTION ON CLIMBING JACKS 6 Claims, 4 Drawing Figs.

[52] US. Cl 254/89, 254/105 [51] Int. Cl B66f7/l2 [50] Field of Search 254/89, 105,106,107. 110

[56] References Cited UNITED STATES PATENTS 2,946,557 7/1960 Suderow 254/ l 06X 2,947,148 8/1960 Young 254/11OX Primary Examiner-Andrew R. J uhasz Assistant ExaminerDavid R. Melton Att0rneyHolman and Stern ABSTRACT: An arrangement for a uniform load distribution and a group of cooperating climbing jacks in which each jack in the group acts on a separate climb rod and includes one or more lifting means. Each climbing jack has associated therewith at least one load transferring hydraulic balancing jack embodying a hydraulic pressure cylinder and hose means hydraulically interconnecting the pressure cylinders of the balancing jacks associated with the group.

PATENTEU JAN 1 919m SHEET 3 [1F 4 ARRANGEMENT FOR EFFECTING UNIFORM LOAD DISTRUBUTION ON CLIMBING .IACKS BACKGROUND OF THE INVENTION Climbing jacks adapted to be moved along a smooth rod are well known particularly in the field of sliding form casting.

Of recent date, climbing jacks have also been utilized in other fields of operation, such as, for example in lifting and lowering heavy loads wherein the practical applicability in combination with hydraulics as a power source renders possible lightweight and simple lifting and lowering equipment in relation to the work volume being handled.

The present invention is an arrangement for eliminating a shortcoming which has limited the applicability of climbing jacks for the lifting and lowering of heavy nonelastic loads in cases when due to the weight and/or spread of the load, aplurality of climbing jacks are required.

This shortcoming is due to the fact that all known climbing jacks which operate on smooth rods have a tendency ,of climbing different distances and which tendency is summarizing. On employing such a number of climbing rods that the nonelastic load and the rods and climbing jacks constitute a statically undetermined system, a very unequal load distribution will develop among the climbing jacks following a number of climbing steps.

This disadvantage is eliminated by the present invention. 1

SUMMARY OF THE INVENTION- The present invention, can, for example, be applied to a group of four climbing jacks which are positioned on a load carrier and which together each by a separate climbing rod must lift or elevate a horizontal and very heavy load. Associated with each climbing jack is at least one load transferring hydraulic balancing or equalizing jack including a'hydraulic pressure cylinder with the pressure cylinders of the balancing jacks associated with the group being hydraulically inter' connected preferably by hoses.

Before the loading of the climbing jacks with the load, each balancing or equalizing jack is supplied with an amount of oil corresponding to approximately 50 percent of the total stroke volume thereof and each balancing jack is provided with a stop valve by means of which the jack can be connected to the other balancing jacks of the group. As the climbing jacks are operated to elevate the load, the stop valves are maintained closed until the load is entirely carried or supported by the climbing jacks andthe system is now statically determined. All of the balancing jacks of the group are subsequently interconnected hydraulically by opening the stop valves.

Hence, the individually different climbing distance of a climbing jack of the group will not effect the climbing of the other jacks of the group whereby the'load will bedistributed uniformly by the common hydraulic pressure in the balancing jacks. By virtue of the limited length of the stroke of the balancing jack, equalizing of the positions of the pistons and the cylinders may be necessary after the jacks climb a longer distance such as, for example, after climbing ten steps. Such an equalizing or levelling is effected by manual or automatic levelling of the balancing jacks of the group which operation may be executed advantageously by interrupting movement of the climbing jacks after a distance of movement which is predetermined for each climbing jack.

Further objects and advantages of the present invention will become more readily apparent from the following detailed description and annexed drawings and in which drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view partly in elevation and partly in cross section of a group which comprises two two-cylinder climbing jacks provided with balancing or equalizing jacks,

FIG. 2 is a diagrammatic view illustrating an embodiment in which four climbing jacks provided'with balancing jacks are connected in two groups for lifting or lowering a load suspended in climb rods,

FIG. 3 is a view generally similar to FIG. 2 of an embodiment in which the climb rods are fixed at an upper load carrier, and the climbing jacks with their balancing jacks are attached to the movable load, and

FIG. 4 is a diagrammatic-view of an embodiment in which the climbing jacks are placed at the movable load and the balancingjacks at the support of the climb rods.

In FIG. 1 two hydraulic climbing jacks generally designated 40 and 40' and each jack comprises two grip heads I, grip members 2, a climb rod 3, two pressure cylinders 4 provided with pistons 5, return springs 25, oil line 6 and a stopcock 7. In FIG. 1 two hydraulic balancing jacks generally designated 80 and 80 and each jack comprises two pressure cylinders 8 provided with pistons 9, a base plate 10 resting on a load carrier 13, a stopcock II and a oil line 12.

The two climbing jacks 40 and 40' are connected by hoses 22 and 23 to a hydraulic pressure pump 20, which is provided with a pump handle 21. The pump, of course, may also be driven in another way. The two balancing jacks 80 and 80' are hydraulically interconnected by a hose 24.

FIGS. 2, 3 and 4 show the lifting/lowering of a load 14 in relation to a load carrier 13. In FIG. 3, the load is attached to a load support 15, and the climbing jacks 40 and 40' as well as thebalancing jacks 80 and'80' are mounted on the lower surface of a carrier member 26 which is connected by rods 27 with the load support 15.

In FIG. 4, the climb rods 3 and 3" are suspended on the balancing jacks80 and 80' by nuts 28 threaded onto the ends of the climb rods jacks and rest on washers 29. The climbing may advantageously be constructed in accordance with US. Pat. No. 3,203,669.

The load carrier 13 may, have its location in different load situation above or below the load I4 and load support 15 respectively.

The invention may, for example, .be applied to the lifting or lowering of a load of 300 tons by using climbing jacks each having a lifting power of 15 tons. In this situation four groups can be applied, each of which comprises five climbing jacks cooperating with each other, with associated balancing jacks according to the invention.

The stroke length of such a climbing jack may be, for example, at maximum 100mm. the stroke length in practice then being for every climbing step, for example, 95 mm. 98 mm. etc.

From the foregoing it will be appreciated that the invention can be employed with a group of four claiming jacks placed on a load carrier and which together in conjunction with a separate climbing rod must elevate a horizontal and very heavy load. At least one load transferring hydraulic balancing or equalizing jacks 80, is associated with each climbing jack 40, 40' and the pressure cylinders of the balancing jacks associated with the group are hydraulically interconnected.

The operation of the assemblage is as follows:

Prior to loading of the climbing jacks with a load, each balancing jack is supplied ,with an amount of ,oil which corresponds to approximately 50 percent of the' total stroke volume thereof and each balancing jack is equipped with a stop valve whereby the jack can be connected to the other balancing jacks of the group. When the climbing jacks are operated to elevate the load, the stop valves are maintained closed until the load is carried entirely by the climbing jacks and the system is now statically determined.

All of the balancing jacks of the group are subsequently hydraulically interconnected by opening the stop valves.

I claim:

l. Arrangement for a uniform load distribution at a group of cooperating climbing jacks, in which each climbing jack in the group acts on a separate, smooth climb rod, and each climbing jack in the group including a load transferring base, a stepwise lifting means, said lifting means being connected to said base by at least one continuously acting hydraulic balancing jack transferring the load and comprising a hydraulic pressure cylinder, and means hydraulically interconnecting the pres sure cylinders of the balancing jacks connected to the climbingjacks of said group.

2. The arrangement according to claim 1, characterized in that at least two balancing jacks are disposed symmetrically in relation to the respective climb rod.

3. The arrangement according to claim 1 including a load carrier with respect to which the load is lifted or lowered, said climbing jacks being supported on the balancing jacks, and said balancingjacks being supported on the load carrier.

4i The arrangement according to claim 1, including a load carrier with respect to which the load is lifted or lowered, a load support for the load, a carrier member connected with anddisposed above the load support, and said climbing jacks and balancingjacks being mounted on the carrier member.

5. The arrangement according to claim 1 including a load carrier with respect to which the load is lifted or lowered, a

- load support for the load, said climbing jacks being connected with the load support and said balancing jacks being connected with the load carrier.

6. An arrangement for a uniform load distribution at a group of cooperating climbingjacks in which eaeh'jack in the group acts on a separate, smooth climb rod, and each climbing jack in the group has at least one l oad transferring means operably connected thereto, a load carrier with respect to which the load is lifted or lowered, each climbing jack including upper and lower heads, grip means for the rod carried by each head a pair of cylinders mounted o'n'the upper head, a piston movable in each cylinder. eachpiston having a piston rod mounted on the lower head a return spring within each cylinder cooperable with the piston and cylinder a-source of pressure fluid, conduit means leading-to each'cylinder and said source. said load transferring means beingdefined by a balancing jack including a pair of cylinders mounted on the lower gripping head of the climbing jack, a piston slidably mounted in each cylinder, a load transferring base on the load carrier, each piston having a piston rod mounted on said load transferring base, a return spring for each piston within each cylinder cooper'able with the piston and cylinder, conduit means interconnecting the cylinders of the balancing jacks connected to the climbing jacks of said group and stop valves in the conduit means. 

1. Arrangement for a uniform load distribution at a group of cooperating climbing jacks, in which each climbing jack in the group acts on a separate, smooth climb rod, and each climbing jack in the group including a load transferring base, a stepwise lifting means, said lifting means being connected to said base by at least one continuously acting hydraulic balancing jack transferring the load and comprising a hydraulic pressure cylinder, and means hydraulically interconnecting the pressure cylinders of the balancing jacks connected to the climbing jacks of said group.
 2. The arrangement according to claim 1, characterized in that at least two balancing jacks are disposed symmetrically in relation to the respective climb rod.
 3. The arrangement according to claim 1 including a load carrier with respect to which the load is lifted or lowered, said climbing jacks being supported on the balancing jacks, and said balancing jacks being supported on the load carrier.
 4. The arrangement according to claim 1, including a load carrier with respect to which the load is lifted or lowered, a load support for the load, a carrier member connected with and disposed above the load support, and said climbing jacks and balancing jacks being mounted on the carrier member.
 5. The arrangement according to claim 1 including a load carrier with respect to which the load is lifted or lowered, a load support for the load, said climbing jacks being connected with the load support and said balancing jacks being connected with the load carrier.
 6. An arrangement for a uniform load distribution at a group of cooperating climbing jacks in which each jack in the group acts on a separate, smooth climb rod, and each climbing jack in the group has at least one load transferring means operably connected thereto, a load carrier with respect to which the load is lifted or lowered, each climbing jack including upper and lower heads, grip means for the rod carried by each head, a pair of cylinders mounted on the upper head, a piston movable in each cylinder, each piston having a piston rod mounted on the lower head, a return spring within each cylinder cooperable with the piston and cylinder, a source of pressure fluid, conduit means leading to each cylinder and said source, said load transferring means being defined by a balancing jack including a pair of cylinders mounted on the lower gripping head of the climbing jack, a piston slidably mounted in each cylinder, a load transferring base on the load carrier, each piston having a piston rod mounted on said load transferring base, a return spring for each piston within each cylinder cooperable with the piston and cylinder, conduit means interconnecting the cylinders of the balancing jacks connected to the climbing jacks of said group and stop valves in the conduit means. 